1. Field of the Invention
This invention relates to a non-aqueous process for the removal of metallic residue, e.g., of a soluble organonickel hydrogenation catalyst such as mixtures of organonickel and alkylaluminum or alkyllithium, from solutions of hydrogenated material such as hydrogenated polymers, e.g., styrene-butadiene, by treating such solutions with non-aqueous acid, for example, glacial acetic acid followed by neutralization with anhydrous base, e.g., anhydrous ammonia, and filtration.
2. Description of the Prior Art
Removal of soluble hydrogenation catalyst residue from hydrogenation solutions has generally comprised treatment with an aqueous solution containing an agent to facilitate removal of said residue. Thus U.S. Pat. No. 3,634,549 describes the removal of hydrogenation catalyst (e.g., nickel octoate/triethylaluminum) residue by treating a solution containing a hydrogenated polymer with dilute hydrochloric acid and water; and U.S. Pat. No. 3,531,448 describes the precipitation of metallic catalyst residue by treatment with aqueous ammonium phosphate followed by filtration. This is disadvantageous if further reactions on the product are to be conducted in an anhydrous solution and/or it is desirable prior to further reaction to remove the catalyst without isolating the hydrogenated material or treating it with aqueous reagents to remove the catalyst.